Riferimento: Server dedicato o virtualizzazione su Cloud?
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Windows Server 2008 Datacenter
OK, so, we’re on the home straight here – just Datacenter edition to go! Stay with me!
Hopefully you understand what I’ve been talking about so far, because it’s very important when devising solutions based on Microsoft server technologies, regardless of the Virtualisation platform. I wouldn’t want to be a customer, who’s paid good money to embrace VMware’s technologies (for example), and been told incorrect information about Windows licenses running on those ESX hosts, which has resulted in the customer buying more licenses that necessary. Not good. It’s therefore critically important that both customers, and partners understand and can articulate this information.
So, what’s the deal with Datacenter edition, and is it too ‘big’ for my business? Well, let’s dip into a little history first – In previous versions of Windows Server, i.e. 2003, you could only buy Datacenter edition on hardware. There was no other channel, bar OEM, that organisations could get hold of Datacenter, so, in many cases, it would have been restricted to the larger organisations who were buying whopping hardware. That’s changed for 2008.
Update - As Mike rightly points out in the comments section "Windows Server 2003 Datacenter became available through normal channels in October 2006 - the same day these virtualization rights were introduced. You still get the rights with Windows Server 2003 and 2008 and can use the downgrade rights for earlier versions of the OS"
For the first time,
Datacenter edition of Windows Server is available through regular Volume Licensing channels, so it’s instantly more mainstream and accessible for many more people, but, why would you want it? Well, if you take Windows Server 2008 Datacenter as an OS, it’s our most scalable version of the Windows Server 2008 versions, supporting the highest number of procs/cores, but feature wise, it’s pretty much the same as Enterprise. Where it changes massively, is when you bring in Virtualisation.
The Hyper-V bits themselves are identical to those in Enterprise, scaling up to 1TB RAM in the physical box, 24 cores with the latest Intel 6-core chips, 64GB RAM per VM etc etc. It’s the Virtualisation licensing that’s pretty darn different than Enterprise. Here’s the scenario:
Imagine we want to achieve a 16:1 consolidation ratio, so, 16 VMs (in this case, Windows Servers) running on 1 pretty powerful box. Seems pretty achievable I’d say, but what’s the most cost effective way of licensing it? Well, so far we have Standard edition, which gives us 1 free VM per assigned license, so we’d need 16 licenses @ $999 each, so we’re talking around $16k. We don’t have much flexibility using Standard edition, plus we can’t use any Failover Clustering, so we’re putting quite a few eggs in one basket here! What are the alternatives?
We have Enterprise edition, which, as I detailed above, provides 4 free running instances per assigned license, so, for 16 VMs, we’d need 4 Enterprise licenses assigned to this box. 4 Enterprise licenses @ $3999 per license weighs in at $16k, so pretty similar to Standard edition really, but with greater scalability and features under the hood. Final option? Datacenter Edition.
Now, first important point, Datacenter edition is licenses per physical processor, not per box, like Enterprise/Standard are. So, in our scenario, imagine the box on the left has 2 physical procs, each with quad cores.
So, in this case, we’d need to assign 2 Datacenter licenses to the box on the left, as it has 2 physical processors. Datacenter licenses go for $2999 per processor. That would mean that this scenario would cost us just under $6k. But what are we getting for our money? I haven’t mentioned any ‘free’ virtual machines yet….
Windows Server 2008 Datacenter Edition, when assigned to a host, allows an unlimited number of free running Windows Server guest OS’s on that host. So, for our scenario, where we want a 16:1 ratio, assigning 2 Datacenter licenses to that box (for a total of just under $6k) gives us what we need, and more. I could double, triple or even quadruple (and more!) the number of Windows Server Guest OS’s on that box, and still only ever pay $6k. This would only change if I upped the number of physical procs in the machine. So, $6k Datacenter, vs. $16k for Standard/Enterprise. Double the ratio to 32:1 and Datacenter is still $6k, but Enterprise & Standard are now coming in at around $32k – in fact, Standard would probably have hit it’s limit by that point, depending on how ‘big’ the VMs are (Standard edition supports 32GB RAM in the host).
The great thing to mention about Datacenter Edition (aside from the great Virtualisation licensing benefits!) is that it really eases the licensing headache around migration of virtual machines between hosts.
If you have a 3 node cluster, each with Datacenter licenses assigned, it will never matter how many Windows Server VMs you’re running on each physical node. You can have 20 VMs on one, 10 on another, and 35 on another, and never have to worry about being incorrectly licensed from a Windows Server perspective. Excellent.
mi stavo preparando già una licenza di win 7 enterprise perchè ho letto che con una licenza di quel tipo posso tirare su fino a 4 win 7 virtualizzati.